Sleep is an important role in your physical health. For example, sleep is involved in healing and repair of your heart and blood vessels. Ongoing sleep deficiency is linked to an increased risk of heart disease, kidney disease, high blood pressure, diabetes, and stroke.

It may seem obvious that sleep is beneficial. Even without fully grasping what sleep does, we know that going without sleep for too long makes us feel terrible, and that getting a good night’s sleep can make us a feel ready to take on the world.

Scientists have gone to great lengths to fully understand sleep’s benefits. In studies of humans and other animals, they have discovered that sleep plays a critical role in immune function, metabolism, memory, learning, and other vital functions. The features in this section explore these discoveries and describe specific ways in which we all benefit from sleep.

Why Do We Sleep, Anyway?

Although scientists aren’t entirely sure why we sleep, they have many ideas about the functions of this mysterious part of our lives. While some of these functions may have deep evolutionary roots, others, such as sleep’s potential role in memory and health, seem particularly relevant to life in the 21st century.

Sleep, Learning, and Memory

It may not be surprising that it is more difficult to take in new information following a night of inadequate or disturbed sleep. What’s more surprising is that it is just an important to get a good night’s sleep after learning something new in order to process and retain the information that has been learned.

Healthy Brain Function and Emotional Well-Being

Sleep helps your brain work properly. While you’re sleeping, your brain is preparing for the next day. It’s forming new pathways to help you learn and remember information. Studies show that a good night’s sleep improves learning. Whether you’re learning math, how to play the piano, how to perfect your golf swing, or how to drive a car, sleep helps enhance your learning and problem-solving skills. Sleep also helps you pay attention, make decisions, and be creative.

Studies also show that sleep deficiency alters activity in some parts of the brain. If you’re sleep deficient, you may have trouble making decisions, solving problems, controlling your emotions and behavior, and coping with change. Sleep deficiency also has been linked to depression, suicide, and risk-taking behavior.